Various approaches to automated or semi-automated three-dimensional object production or rapid prototyping & manufacturing ("RP&M") have become available in recent years, characterized in that each proceeds by building up three-dimensional objects from computer data descriptive of the object in an additive manner from a plurality of formed and adhered laminae. These laminae are sometimes called object cross-sections, layers of structure, object layers, layers of the object, or simply layers (if the context makes it clear that solidified structure of appropriate shape is being referred to). Each lamina represents a cross-section of the three-dimensional object. Typically lamina are formed and adhered to a stack of previously formed and adhered laminae. In some RP&M technologies, techniques have been proposed which deviate from a strict layer-by-layer build up process wherein only a portion of an initial lamina is formed and prior to the remaining portion(s) of the initial lamina at least one subsequent lamina is at least partially formed.
According to one such approach, a three-dimensional object is built up by applying successive layers of unsolidified, flowable material to a working surface, and then selectively exposing the layers to synergistic stimulation in desired patterns, causing the layers to selectively harden into object laminae which adhere to previously-formed object laminae. In this approach, material is applied to the working surface both to areas which will not become part of an object lamina, and to areas which will become part of an object lamina. Typical of this approach is Stereolithography (SL), as described in U.S. Reexamination Certificate No. B1 4,575,330, to Hull. According to one embodiment of Stereolithography, the synergistic stimulation is radiation from a UV laser, and the material is a photopolymer. Another example of this approach is Selective Laser Sintering (SLS), as described in U.S. Pat. No. 4,863,538, to Deckard, in which the synergistic stimulation is IR radiation from a CO.sub.2 laser and the material is a sinterable powder. A third example is Three-dimensional Printing (3DP) and Direct Shell Production Casting (DSPC), as described in U.S. Pat. Nos. 5,340,656 and 5,204,055, to Sachs, et al., in which the synergistic stimulation is a chemical binder, and the material is a powder consisting of particles which bind together upon selective application of the chemical binder.
According to a second such approach, an object is formed by successively cutting object cross-sections having desired shapes and sizes out of sheets of material to form object lamina. Typically in practice, the sheets of paper are stacked and adhered to previously cut sheets prior to their being cut, but cutting prior to stacking and adhesion is possible. Typical of this approach is Laminated Object Manufacturing (LOM), as described in U.S. Pat. No. 4,752,352, to Feygin in which the material is paper, and the means for cutting the sheets into the desired shapes and sizes is a CO.sub.2 laser. U.S. Pat. 5,015,312 to Kinzie also addresses LOM.
Various issues arise with respect to the foregoing approaches however. Though the approach involving a photopolymer and UV laser has come into wide use and produces highly accurate objects, the use of photopolymers presents handling, disposal and toxicity issues. Furthermore, where lasers are used in any of the above approaches, safety concerns exist.
In addition, systems embodying any of the foregoing approaches may be generally expensive to purchase and operate because, for example, components such as lasers and scanning mirror systems are themselves expensive and/or need replacement or calibration over time. Furthermore, any of the foregoing approaches may require too much space and/or require a high level of expertise in operating the building apparatus which may prohibit their use in a typical office setting.
More recently, a third approach to rapid prototyping and manufacturing has emerged whereby an object cross-section is formed by selectively dispensing an unsolidified, flowable material onto a working surface in desired patterns in areas which will become part of the object cross-section. The material is then allowed or caused to solidify or otherwise physically transform to form the object cross-section and simultaneously adhere to the previous object cross-section. These steps are then repeated to successively build up the object cross-section by cross-section. A primary difference between this approach and earlier approaches, e.g., Stereolithography, is that the material is typically selectively dispensed only in those areas which will become part of an object cross-section.
Typical of this approach is thermal stereolithography as described in U.S. Pat. No. 5,141,680 to Almquist et al. Also typical of this approach is Fused Deposition Modeling as described in U.S. Pat. Nos. 5,121,329 and 5,340,433 to Crump in which a thermosettable material is dispensed while in a molten state and then hardens after being allowed to cool. Another example is described in U.S. Pat. No. 5,260,009 to Penn. Another example is Ballistic Particle Manufacturing as described in U.S. Pat. Nos. 4,665,492; 5,134,569 and 5,216,616 to Masters, in which ballistic particles are directed to specific locations to form object cross-sections.
However, in certain of the embodiments of the patents directed to this third approach, little detail is provided as to the actual hardware, software or other system aspects used to implement this approach. Furthermore, these previous embodiments may also involve excessive noise and generally do not describe how such apparatus or methods might be implemented to ease operation such that the approach might be used by various personnel in an office environment. Additionally, these previous systems and methods are typically slow and often require trained operators.
Accordingly, there is a need in the three-dimensional modeling or rapid prototyping and manufacturing field for a system and associated method for forming three-dimensional objects which may produce objects safely, easily and within an office environment. There is a further need for this system and associated method to be less expensive and produce objects quicker and more reliably than previous systems or methods.
All patents referred to in this specification are hereby incorporated by reference as if set forth in full.